That quake was triggered by changes in tectonic forces caused by 200
years of underground coal mining, according to a study by Christian D.
Klose of Columbia University’s Lamont-Doherty Earth Observatory in
Palisades, New York.

The quake wasn’t enormous, but Australia isn’t generally considered to be seismically active and the city’s buildings weren’t designed to withstand a temblor of that magnitude, Klose said.

All told, he added, the monetary damage done by the earthquake exceeded the total value of the coal extracted in the area.

[snips]

The removal of millions of tons of coal from the area caused much of the stress that triggered the Newcastle quake, Klose said.

But even more significant was groundwater pumping needed to keep the mines from flooding.

"For each ton of coal produced, 4.3 times more water was extracted," Klose said.

More better scarier:

Klose has identified more than 200 human-caused temblors, mostly in the past 60 years. "They were rare before World War II," he said.

Most were caused by mining, he said, but nearly one-third came from reservoir construction.

Oil and gas production can also trigger earthquakes, he added.

Three of the biggest human-caused earthquakes of all time, he pointed out, were a trio that occurred in Uzbekistan’s Gazli natural gas field between 1976 and 1984.

Each of the three had a magnitude greater than 6.8, and the largest had a magnitude of 7.3.